Steering column assemblies for vehicles are available that collapse during a frontal collision. Energy absorption systems are used with the collapsible columns. These energy absorption systems cooperate with air bags to minimize the force exerted on a vehicle driver during a collision.
Current steering column energy absorption systems can take many forms. One such common form employs a column bracket that is secured through a releasable connection to a vehicle structure such as under a dash board. Energy absorption straps or coils become engaged as the releasable connection yields to the overwhelming force of a frontal collision. Energy absorption straps or coils, employed in many energy absorption systems, are expensive. These energy absorption straps or coils can be located in the releasable mounting connection of the column bracket to the vehicle structure, or between the steering column and an intermediate bracket. Energy absorption straps and coils require multiple threaded fasteners, and their assembly can be labor intensive, physically taxing and time consuming.
In some vehicle applications, special mounting requirements are imposed upon the steering column assembly to improve column stiffness, or to control the collapsing direction of the column in the event of a collision. Typically, a rigid mounting plate is required to accomplish either or both of these functions, or is incorporated into a steering column assembly for other reasons. A mounting plate, when required, typically provides at least three to four mounting points and may be fabricated from a durable gauge formed metal or plastic material. Thus, a mounting plate adds both weight and cost to the steering column assembly. This extra weight and cost is in addition to the cost, weight and complexity of energy absorption straps or coils that are required for collision management purposes.
Therefore, it would be desirable to provide an energy absorption system for steering column assemblies which require a mounting plate that is less expensive to manufacture, lighter in weight, and more easily assembled to a motor vehicle.